Automatic feed device for rotary drill bits



Dec. 16, 1930. J. w. HAUK AUTOMATIC FEED DEVICE FOR ROTARY DRILL BITSFiled March '1, 1928 a? V I m, m I... a

m 2 al /12% I INVENTOR.

A TTORNEYS Patented Dec. 16, 1930 UNITED STATES PATENT OFFICE JOHN W.HAUK, F WHITTIER, CALIFORNIA, ASSIGNOR OF ONE- HALF TO LEROY G.

GATES, OF BAKERSFIELD, CALIFORNIA AUTOMATIC FEED DEVICE'FOR ROTARY DRILLBITS Application filed March 1, 1928. Serial No. 258,170.

My invention relates to the well drilling art, and more particularly toprotective devices for rotary drill bits.

The principal object of the invention is to provide means for preventingbreakage of the drill stem or drill bit. Such breakage is comparativelycommon, particularly in the lowermost sections of the drill stem, and isdue to the twisting of the stem caused by the unequal resistance whichthe cutting faces of the bit encounters. Each time that the bit strikesan obstruction or hard spot, the resistance is increased, and the stemis twisted until such resistance is overcome, whereupon the stemuntwists, causing the bit to rotate with increased speed. If a secondobstruction is encountered during such increased speed, a sudden andviolent shock ensues. In practice this occurs continually, so that thestem and bit are subject not only to repeated and violent torsionalstrains, but to excessive vibration as well. On account of the greatlength of the stem, the wei ht of the stem and bit, and the necessity orthe greatest possible speed of operation, this strain and vibrationcauses frequent failure, especially in the lowermost joints of the stem,resultin%in costly waste of time and labor.

y the use of a device embodying my invention, the torsional strain onthe stem is rendered practically uniform, and the vibration is greatlyreduced, thus minimizing breakage. A further advantage in my inventionis that it may be applied to any existing drill bit or stem withoutchanging the method of operation or interfering with the action of thebit or of the circulating fluid.

It should be understood that the form, arrangement, and construction ofthe several parts of my invention, as herein described and illustrated,may be varied, within the scope of the claims hereto appended, withoutdeparting from the spirit of the invention as set forth in said claims.

With this in view, several preferred embodiments of m invention will nowbe described fully with reference to the accompanying drawings, whereinFig. 1 is a part sectional elevation of one 50 form of my device.

Fig. 2 is a vertical sectional detail illustrating a second form ofdifferential connection between the relatively movable sleeves.

Fig. 3 is a vertical sectional detail illustrating one form of retardingdevice that may be used to dampen the relative movement of the sleeve.

Fig. 4 is a vertical sectional detail of a second form of retarding ordampening device. 0

Fig. 5 is a horizontal section illustrating a third form of differentialconnection between the sleeves.

Fig. 6 is a vertical sectional detail of the form shown in Fig. 5.

Fig. 7 is a vertical sectional detail illustrating a difierentarrangement of the spring shown in Fig. 1.

In the drawings, and referring for the moment to Fig. 1, the referencenumeral 1 desi nates a portion of the usual drill stem, to w ich-isconnected, by a suitable coupling 2, a sleeve 3 of slightly increaseddiameter.

A second and smaller sleeve 4 is movably fitted within the sleeve 3, andits lower end is connected with the drill bit 5. A connection isemployed between the sleeves 3 and 4, which will transmit the rotativedriving force from the stem 1 to the bit 5, and which will permit theinner sleeve 4 with said bit 5 to rise independently of the outer sleeve3 and said stem 1, thus permitting the bit to rise over an obstruction.In its simplest form, this connection is a helical sliding one, of anysuitable construction, similar in efiect to a screw thread. As oneexample of a simple type of such construction I have shown, in Fig. 1,helical slots 6 in the outer sleeve 3, and lugs 7 projecting from theinner sleeve 4 and slidable in said slots.

The effect of such an arrangement, assuming the proper direction ofrotation of the stem 1, is to cause the inner sleeve 4 to rise wheneverthe resistance to the rotation of the bit 5 increases, and such rise, ofcourse, immediately decreases the resistance, so that a practicallyuniform torque is maintained. Suitable means must be fprovided forpreventing the inner sleeve 4 om dro ping out,

which can be done for example. "ys closing the lower ends of the slots6, as shown at 8.

If the weight of the inner sleeve 4 and the bit 5 are not sufflcient togive the bit the necessary efl'ectiveness, a suitable resilient membermay be interposed between the two sleeves in such a manner as toincrease either the downward force or the rotative force, or both, onthe bit. One form of such a resilient member is shown as a helicalspring 9, interposed between the upper end of the inner sleeve 4 and ashoulder 10 in the outer sleeve 3. Such a spring increases the downwardforce on the bit, and, if its ends are respectively connected with thetwo sleeves, as shown at 11, it also directly increases the rotativeforce on said bit. It is to be understood, of course, that theconnections 11 may be omitted, in which case the spring will directlyincrease only the downward force on the bit.

With the spring 9 positioned as in Fig. 1, the entire weight of thedrill stem 1 may rest upon the bit. Such a weight may be too great forbest results in certain formations, and it has the further disadvantageof increasing as the depth of the hole increases. Therefore, I mayarrange the spring 9 as shown in Fig. 7, acting between the top of theinner sleeve 4 and a tubular weight 12 freely slidable within the outersleeve 3, said outer sleeve being long enough in this case toaccommodate said weight. In this arrangement the weight or downwardforce upon the bit is constant, and can be fixed at the desired value byproperly proportioning the freely slidable tube 12.

The advantage in the use of a spring as shown in Figs. 1 and 7 is thatthe downward force on the bit can be increased to the best point,without adding to such force the effect of the inertia of the long drillstem. Obviously, the desired weight could be applied tothe bit merely byadding a section of stem between the inner sleeve 4 and the bit, butsuch an arrangement would also add the effect of the inertia of suchstem section to its weight whenever the bit started to rise. Byinterposing a spring between the weight and the bit, however, the effectof such inertia is overcome.

A second method of applying a controlled downward force on the bit isillustrated in Fig. 1. Rotary bits of this type are commonly used with acirculating mud fluid, which is forced down through the hollow drillstem and out through suitable discharge orifices in the bit, and whichrises outside the stem, carrying with it the cuttings. The constructionof my device is such that nointerference is presented to the flow ofsuch fluid, which passes freely through the inner sleeve 4. By makingthe discharge orifice in the bit, as indicated at 13, of smaller areathan the area of the stem 1, the pressure of the mud fluid will effect adownward force on the bit, which can be regulated by varying saidpressure. The spring, arranged as shown in either Fig. 1 or Fig. 7, mayor may not be used in connection with the fluid pressure, as desired.

In certain cases is may be desirable to dampen the action of thedifi'erential connection between the sleeves 3 and 4. This can beaccomplished by friction as illustrated in Fig. 3, in which suitablepacking 14 is secured in the upper end of the inner sleeve 4 by a ring15, and has frictional contact with the inner surface of the outersleeve 3. A second example of a dampening means is illustrated in Fig.4, wherein the upper end portion of the inner sleeve 4 is formed with anannular recess 16 which is filled with a suitable fluid. The outersleeve 3 has a ring 17, positioned to be normally about mid-way of thelength of the recess 16. A suitably proportioned restrictive passage, asshown at 18, is provided in said ring 17 or between it and the surfaceof the sleeve 4, through which the fluid must pass upon verticalmovement of the inner sleeve. Thus a dash-pot effect is produced, whichretards or dampens the relative movement between the sleeves.

A second form of helical connection between the inner sleeve 4 and theouter sleeve 3 is shown in Fig. 2, in which said sleeves are formed withhelical matched complementary grooves 19 and 20 respectively, formingchannels in which ride a series of steel balls 21. The action, ofcourse, is exactly similar to that of the slot and lug connection shownin Fig. 1.

A third form of difierential connection between the sleeves 3 and 4 isshown in Figs. 5 and 6, in which the outer sleeve 3 is provided with aninterior horizontal ring gear 22. The inner sleeve 4 is formed withdiametrically opposite vertical slots 23, one face of each slot beinprovided with teeth forming a rack 24. 1 spur pinion 25 is mounted ineach slot to mesh with the rack thereof,

and is fixed to a bevel pinion 26 which meshes with the ring gear 22.Any suitable means may be provided for retaining the pinions inposition, as for example a horizontal spindle 27 upon which the twopairs of pinions freely revolve. Thus relative rotation between the twosleeves causes relative vertical movement, which is the same effectproduced by the helical connections shown in Figs. 1 and 2.

In said helical connections, the relation between the turning andlifting forces exerted on the bit can be varied by changing the pitch ofthe helical slots 6 or grooves 19 and 20. The same efiect can beaccomplished in the geared connection shown in Figs. 5 and 6 by changingthe relative diameters of the pinions 25 and 26.

It will be apparent to those skilled in the art, and should be sounderstood, that either or both of the two forms of dampening devicesshown in Figs. 3 and 4 may or may not be used in connection with any oneof the forms of difi'erential connecting means shown in Figs. 1, 2, 5and 6. Similarly either of the loading spring arrangements shown inFigs. 1 and 7 may or may not be used with any of said differentialconnecting means, and with either or both of the dampening devices.Also, the fluid pressure loading means indicated in Fig. 1 may be usedwith any of the other forms and devices described.

Other changes and variations will suggest themselves to those skilled inthe art, and although I have shown and described certain forms of theinvention andparts thereof, I do not wish to be understood asrestricting myself thereto. For example, I have described the device asapplied at the lower end of the drill stem in fairly close proximity tothe drill bit. This is the preferred location, for the reason that itrelieves the bit of the effect of the inertia of the stem, allowing itto respond instantly to sudden increases in resistance or torquereaction, but it will be apparent that the device may be used at anypoint in the length of the stem, or even at the surface. Moreover, suchvariations as placing the stem carried sleeve inside the bit carryingsleeve, instead of outside as shown and described, and the use of otherwell known forms of springs for loading the bit in lace of the helicalspring shown in the drawlngs, would be obvious to any skilled me-,

chanic, and have consequently been omitted from the drawings to avoidconfusion.

It is desirable that the operator at the surface have some indication ofthe relative positions of the differentially connected sleeves, so thathe may know when the bit touches bottom and, more important still, whenthe weight of the drill stem has moved said sleeves to the limit oftheir relative travel, since under the latter condition the differentialconnection is inoperative. This indication ,can be given in a number ofways, but most convenientl by a change in the pressure of the circulatmgmud fluid. One example of a simple means foLprodncing such pressurechange is illustrated in FigsQl and 2, wherein 28 and 29 are ports inthe outer and inner" sleeves respectively, positioned to register whenthe bit-carryingsleeve reaches or approaches the upper limit of itsmovement in the stem carried sleeve. When said ports register, a freeoutlet is provided for the mud fluid, and the pressure thereof at thesurface drops, thus giving the operator the desired indication.Obviously, the same means, although not shown, may be employed forvarying the fluid pressure when the bit carrying sleeve is at the lowerlimit of its relative movement, or at any intermediate point.

A second means for indicating the relative positions of the sleeves isillustrated in Fig. 3, wherein 30 is a port in a head 31 in the closesthe port 30, thereby cutting off the flow of mud fluid and increasingits pressure at the surface.

The pressure varying means shown 1n Figs.

-1 and 3 may be combined in the same apparatus, as will be readilyunderstood, the free discharge ports 28 and 29 being used, for example,to lower the fluid pressure when the bit is at its lower limit, and thevalve arrangement 30-32 being used to increase said pressure when thebit is at its upper limit. Obviously, either or both such means may beused with any of the described forms of differential connection, andwith any of the described loading and retarding means.

I claim 1. In a rotary well drilling apparatus, including a drill stemand a drill bit, a pair of relatively movable members, one carried bysaid stem and the other carrying said bit; gears carried by saidmembers; and pinions meshing with said gears and connecting said membersfor relative movement in response to variations in the torque reactionof the bit.

2. In a rotary well drilling apparatus, in-

cluding a drill stem and a drill bit, a pair of relatively movablemembers fitted one within the other, one being carried by said stem andthe other carrying said bit; a substantially horizontal gear carried byone of said members a toothed rack carried by the other member andangularly positioned with respect to the plane of said gear; andconnected pinions engaging said gear and said rack and adapting saidmembers for relative movement in response to variations in the torquereaction of the bit. 1 3. In a rotary well drilling apparatus includinga drill stem and a drill bit; a pair of members secured respectively tosaid stem and said bit, said members fitting one within the other forrelative vertical and rotative movement; a torque transmittingconnection between said members, said connections causing relativevertical movement between said members in response to variations in thetorque transmitted thereby; a weight movably associatedv with both saidmembers; and cushioning means interposed between said weight and the bitcarrying member.

4. In a'rotary well drilling apparatus including a drill stem and adrill bit; a pair of members secured respectively to said stem and saidbit, said members fitting one within the other for relative vertical androtative movement; a torque transmitting connection between saidmembers, said connection causing relative vertical movement between saidmembers in response to variations in the torque transmittedthereby;means carried by one of said members and adapted for frictional contactwith the other member; and adjusting means for varying the amount offriction produced by said contact.

5. In a rotary well drilling apparatus including a, drill stem and adrill bit; a pair of hollow members adapted to conduct fluid underpressure to said bit, said members being secured respectively to saidstem and said bit and fitting one within the other for relative verticaland rotative movement; and said members'having cooperating portspositioned to be moved into and out of register upon said relativemovement; and atorque transmitting connection between said mem-' bers,said connection causing relative vertical movement between sald membersin response to var ations in the torque transmitted there- In testimonywhereof I have signed my name to this specification.

JOHN W. HAUK.

